Power drawn into your CPU cooler is adjusted depending on its temperature. An idle CPU does not generate as much heat, requires less active cooling, and hence slower fan speeds will be sufficient. Further this also reduces the overall ambient noise of your PC and it’s handled automatically with little risk to your PC components.

While PWM fan controllers are very common in today’s PC industry and available on most mainboards, there is often only one or two such PWM headers, reserved for the CPU and or the chipset fans. One way this excellent noise reduction idea can be extended to the numerous case fans inside a typical PC is by utilizing a GELID PWM splitter.